1 //! See `CompletionContext` structure.
3 use hir::{Local, ScopeDef, Semantics, SemanticsScope, Type};
4 use ide_db::base_db::{FilePosition, SourceDatabase};
5 use ide_db::{call_info::ActiveParameter, RootDatabase};
7 algo::{find_covering_element, find_node_at_offset},
8 ast, match_ast, AstNode, NodeOrToken,
10 SyntaxNode, SyntaxToken, TextRange, TextSize,
17 fn_is_prev, for_is_prev2, has_bind_pat_parent, has_block_expr_parent,
18 has_field_list_parent, has_impl_as_prev_sibling, has_impl_parent,
19 has_item_list_or_source_file_parent, has_ref_parent, has_trait_as_prev_sibling,
20 has_trait_parent, if_is_prev, inside_impl_trait_block, is_in_loop_body, is_match_arm,
26 /// `CompletionContext` is created early during completion to figure out, where
27 /// exactly is the cursor, syntax-wise.
29 pub(crate) struct CompletionContext<'a> {
30 pub(super) sema: Semantics<'a, RootDatabase>,
31 pub(super) scope: SemanticsScope<'a>,
32 pub(super) db: &'a RootDatabase,
33 pub(super) config: &'a CompletionConfig,
34 pub(super) position: FilePosition,
35 /// The token before the cursor, in the original file.
36 pub(super) original_token: SyntaxToken,
37 /// The token before the cursor, in the macro-expanded file.
38 pub(super) token: SyntaxToken,
39 pub(super) krate: Option<hir::Crate>,
40 pub(super) expected_type: Option<Type>,
41 pub(super) name_ref_syntax: Option<ast::NameRef>,
42 pub(super) function_syntax: Option<ast::Fn>,
43 pub(super) use_item_syntax: Option<ast::Use>,
44 pub(super) record_lit_syntax: Option<ast::RecordExpr>,
45 pub(super) record_pat_syntax: Option<ast::RecordPat>,
46 pub(super) record_field_syntax: Option<ast::RecordExprField>,
47 pub(super) impl_def: Option<ast::Impl>,
48 /// FIXME: `ActiveParameter` is string-based, which is very very wrong
49 pub(super) active_parameter: Option<ActiveParameter>,
50 pub(super) is_param: bool,
51 /// If a name-binding or reference to a const in a pattern.
52 /// Irrefutable patterns (like let) are excluded.
53 pub(super) is_pat_binding_or_const: bool,
54 pub(super) is_irrefutable_pat_binding: bool,
55 /// A single-indent path, like `foo`. `::foo` should not be considered a trivial path.
56 pub(super) is_trivial_path: bool,
57 /// If not a trivial path, the prefix (qualifier).
58 pub(super) path_qual: Option<ast::Path>,
59 pub(super) after_if: bool,
60 /// `true` if we are a statement or a last expr in the block.
61 pub(super) can_be_stmt: bool,
62 /// `true` if we expect an expression at the cursor position.
63 pub(super) is_expr: bool,
64 /// Something is typed at the "top" level, in module or impl/trait.
65 pub(super) is_new_item: bool,
66 /// The receiver if this is a field or method access, i.e. writing something.$0
67 pub(super) dot_receiver: Option<ast::Expr>,
68 pub(super) dot_receiver_is_ambiguous_float_literal: bool,
69 /// If this is a call (method or function) in particular, i.e. the () are already there.
70 pub(super) is_call: bool,
71 /// Like `is_call`, but for tuple patterns.
72 pub(super) is_pattern_call: bool,
73 /// If this is a macro call, i.e. the () are already there.
74 pub(super) is_macro_call: bool,
75 pub(super) is_path_type: bool,
76 pub(super) has_type_args: bool,
77 pub(super) attribute_under_caret: Option<ast::Attr>,
78 pub(super) mod_declaration_under_caret: Option<ast::Module>,
79 pub(super) unsafe_is_prev: bool,
80 pub(super) if_is_prev: bool,
81 pub(super) block_expr_parent: bool,
82 pub(super) bind_pat_parent: bool,
83 pub(super) ref_pat_parent: bool,
84 pub(super) in_loop_body: bool,
85 pub(super) has_trait_parent: bool,
86 pub(super) has_impl_parent: bool,
87 pub(super) inside_impl_trait_block: bool,
88 pub(super) has_field_list_parent: bool,
89 pub(super) trait_as_prev_sibling: bool,
90 pub(super) impl_as_prev_sibling: bool,
91 pub(super) is_match_arm: bool,
92 pub(super) has_item_list_or_source_file_parent: bool,
93 pub(super) for_is_prev2: bool,
94 pub(super) fn_is_prev: bool,
95 pub(super) incomplete_let: bool,
96 pub(super) locals: Vec<(String, Local)>,
99 impl<'a> CompletionContext<'a> {
101 db: &'a RootDatabase,
102 position: FilePosition,
103 config: &'a CompletionConfig,
104 ) -> Option<CompletionContext<'a>> {
105 let sema = Semantics::new(db);
107 let original_file = sema.parse(position.file_id);
109 // Insert a fake ident to get a valid parse tree. We will use this file
110 // to determine context, though the original_file will be used for
111 // actual completion.
112 let file_with_fake_ident = {
113 let parse = db.parse(position.file_id);
114 let edit = Indel::insert(position.offset, "intellijRulezz".to_string());
115 parse.reparse(&edit).tree()
117 let fake_ident_token =
118 file_with_fake_ident.syntax().token_at_offset(position.offset).right_biased().unwrap();
120 let krate = sema.to_module_def(position.file_id).map(|m| m.krate());
122 original_file.syntax().token_at_offset(position.offset).left_biased()?;
123 let token = sema.descend_into_macros(original_token.clone());
124 let scope = sema.scope_at_offset(&token.parent(), position.offset);
125 let mut locals = vec![];
126 scope.process_all_names(&mut |name, scope| {
127 if let ScopeDef::Local(local) = scope {
128 locals.push((name.to_string(), local));
131 let mut ctx = CompletionContext {
141 name_ref_syntax: None,
142 function_syntax: None,
143 use_item_syntax: None,
144 record_lit_syntax: None,
145 record_pat_syntax: None,
146 record_field_syntax: None,
148 active_parameter: ActiveParameter::at(db, position),
150 is_pat_binding_or_const: false,
151 is_irrefutable_pat_binding: false,
152 is_trivial_path: false,
159 dot_receiver_is_ambiguous_float_literal: false,
161 is_pattern_call: false,
162 is_macro_call: false,
164 has_type_args: false,
165 attribute_under_caret: None,
166 mod_declaration_under_caret: None,
167 unsafe_is_prev: false,
169 block_expr_parent: false,
170 bind_pat_parent: false,
171 ref_pat_parent: false,
173 has_trait_parent: false,
174 has_impl_parent: false,
175 inside_impl_trait_block: false,
176 has_field_list_parent: false,
177 trait_as_prev_sibling: false,
178 impl_as_prev_sibling: false,
180 has_item_list_or_source_file_parent: false,
183 incomplete_let: false,
187 let mut original_file = original_file.syntax().clone();
188 let mut hypothetical_file = file_with_fake_ident.syntax().clone();
189 let mut offset = position.offset;
190 let mut fake_ident_token = fake_ident_token;
192 // Are we inside a macro call?
193 while let (Some(actual_macro_call), Some(macro_call_with_fake_ident)) = (
194 find_node_at_offset::<ast::MacroCall>(&original_file, offset),
195 find_node_at_offset::<ast::MacroCall>(&hypothetical_file, offset),
197 if actual_macro_call.path().as_ref().map(|s| s.syntax().text())
198 != macro_call_with_fake_ident.path().as_ref().map(|s| s.syntax().text())
202 let hypothetical_args = match macro_call_with_fake_ident.token_tree() {
206 if let (Some(actual_expansion), Some(hypothetical_expansion)) = (
207 ctx.sema.expand(&actual_macro_call),
208 ctx.sema.speculative_expand(
214 let new_offset = hypothetical_expansion.1.text_range().start();
215 if new_offset > actual_expansion.text_range().end() {
218 original_file = actual_expansion;
219 hypothetical_file = hypothetical_expansion.0;
220 fake_ident_token = hypothetical_expansion.1;
226 ctx.fill_keyword_patterns(&hypothetical_file, offset);
227 ctx.fill(&original_file, hypothetical_file, offset);
231 /// Checks whether completions in that particular case don't make much sense.
233 /// - `fn $0` -- we expect function name, it's unlikely that "hint" will be helpful.
234 /// Exception for this case is `impl Trait for Foo`, where we would like to hint trait method names.
235 /// - `for _ i$0` -- obviously, it'll be "in" keyword.
236 pub(crate) fn no_completion_required(&self) -> bool {
237 (self.fn_is_prev && !self.inside_impl_trait_block) || self.for_is_prev2
240 /// The range of the identifier that is being completed.
241 pub(crate) fn source_range(&self) -> TextRange {
242 // check kind of macro-expanded token, but use range of original token
243 let kind = self.token.kind();
244 if kind == IDENT || kind == UNDERSCORE || kind.is_keyword() {
245 mark::hit!(completes_if_prefix_is_keyword);
246 self.original_token.text_range()
248 TextRange::empty(self.position.offset)
252 fn fill_keyword_patterns(&mut self, file_with_fake_ident: &SyntaxNode, offset: TextSize) {
253 let fake_ident_token = file_with_fake_ident.token_at_offset(offset).right_biased().unwrap();
254 let syntax_element = NodeOrToken::Token(fake_ident_token);
255 self.block_expr_parent = has_block_expr_parent(syntax_element.clone());
256 self.unsafe_is_prev = unsafe_is_prev(syntax_element.clone());
257 self.if_is_prev = if_is_prev(syntax_element.clone());
258 self.bind_pat_parent = has_bind_pat_parent(syntax_element.clone());
259 self.ref_pat_parent = has_ref_parent(syntax_element.clone());
260 self.in_loop_body = is_in_loop_body(syntax_element.clone());
261 self.has_trait_parent = has_trait_parent(syntax_element.clone());
262 self.has_impl_parent = has_impl_parent(syntax_element.clone());
263 self.inside_impl_trait_block = inside_impl_trait_block(syntax_element.clone());
264 self.has_field_list_parent = has_field_list_parent(syntax_element.clone());
265 self.impl_as_prev_sibling = has_impl_as_prev_sibling(syntax_element.clone());
266 self.trait_as_prev_sibling = has_trait_as_prev_sibling(syntax_element.clone());
267 self.is_match_arm = is_match_arm(syntax_element.clone());
268 self.has_item_list_or_source_file_parent =
269 has_item_list_or_source_file_parent(syntax_element.clone());
270 self.mod_declaration_under_caret =
271 find_node_at_offset::<ast::Module>(&file_with_fake_ident, offset)
272 .filter(|module| module.item_list().is_none());
273 self.for_is_prev2 = for_is_prev2(syntax_element.clone());
274 self.fn_is_prev = fn_is_prev(syntax_element.clone());
275 self.incomplete_let =
276 syntax_element.ancestors().take(6).find_map(ast::LetStmt::cast).map_or(false, |it| {
277 it.syntax().text_range().end() == syntax_element.text_range().end()
283 original_file: &SyntaxNode,
284 file_with_fake_ident: SyntaxNode,
287 // FIXME: this is wrong in at least two cases:
288 // * when there's no token `foo($0)`
289 // * when there is a token, but it happens to have type of it's own
290 self.expected_type = self
294 let ty = match_ast! {
296 ast::Pat(it) => self.sema.type_of_pat(&it),
297 ast::Expr(it) => self.sema.type_of_expr(&it),
304 self.attribute_under_caret = find_node_at_offset(&file_with_fake_ident, offset);
306 // First, let's try to complete a reference to some declaration.
307 if let Some(name_ref) = find_node_at_offset::<ast::NameRef>(&file_with_fake_ident, offset) {
308 // Special case, `trait T { fn foo(i_am_a_name_ref) {} }`.
310 if is_node::<ast::Param>(name_ref.syntax()) {
311 self.is_param = true;
314 // FIXME: remove this (V) duplication and make the check more precise
315 if name_ref.syntax().ancestors().find_map(ast::RecordPatFieldList::cast).is_some() {
316 self.record_pat_syntax =
317 self.sema.find_node_at_offset_with_macros(&original_file, offset);
319 self.classify_name_ref(original_file, name_ref, offset);
322 // Otherwise, see if this is a declaration. We can use heuristics to
323 // suggest declaration names, see `CompletionKind::Magic`.
324 if let Some(name) = find_node_at_offset::<ast::Name>(&file_with_fake_ident, offset) {
325 if let Some(bind_pat) = name.syntax().ancestors().find_map(ast::IdentPat::cast) {
326 self.is_pat_binding_or_const = true;
327 if bind_pat.at_token().is_some()
328 || bind_pat.ref_token().is_some()
329 || bind_pat.mut_token().is_some()
331 self.is_pat_binding_or_const = false;
333 if bind_pat.syntax().parent().and_then(ast::RecordPatFieldList::cast).is_some() {
334 self.is_pat_binding_or_const = false;
336 if let Some(Some(pat)) = bind_pat.syntax().ancestors().find_map(|node| {
339 ast::LetStmt(it) => Some(it.pat()),
340 ast::Param(it) => Some(it.pat()),
345 if pat.syntax().text_range().contains_range(bind_pat.syntax().text_range()) {
346 self.is_pat_binding_or_const = false;
347 self.is_irrefutable_pat_binding = true;
351 if is_node::<ast::Param>(name.syntax()) {
352 self.is_param = true;
355 // FIXME: remove this (^) duplication and make the check more precise
356 if name.syntax().ancestors().find_map(ast::RecordPatFieldList::cast).is_some() {
357 self.record_pat_syntax =
358 self.sema.find_node_at_offset_with_macros(&original_file, offset);
363 fn classify_name_ref(
365 original_file: &SyntaxNode,
366 name_ref: ast::NameRef,
369 self.name_ref_syntax =
370 find_node_at_offset(&original_file, name_ref.syntax().text_range().start());
371 let name_range = name_ref.syntax().text_range();
372 if ast::RecordExprField::for_field_name(&name_ref).is_some() {
373 self.record_lit_syntax =
374 self.sema.find_node_at_offset_with_macros(&original_file, offset);
379 .ancestors_with_macros(self.token.parent())
380 .take_while(|it| it.kind() != SOURCE_FILE && it.kind() != MODULE)
381 .find_map(ast::Impl::cast);
383 let top_node = name_ref
386 .take_while(|it| it.text_range() == name_range)
390 match top_node.parent().map(|it| it.kind()) {
391 Some(SOURCE_FILE) | Some(ITEM_LIST) => {
392 self.is_new_item = true;
398 self.use_item_syntax =
399 self.sema.ancestors_with_macros(self.token.parent()).find_map(ast::Use::cast);
401 self.function_syntax = self
403 .ancestors_with_macros(self.token.parent())
404 .take_while(|it| it.kind() != SOURCE_FILE && it.kind() != MODULE)
405 .find_map(ast::Fn::cast);
407 self.record_field_syntax = self
409 .ancestors_with_macros(self.token.parent())
411 it.kind() != SOURCE_FILE && it.kind() != MODULE && it.kind() != CALL_EXPR
413 .find_map(ast::RecordExprField::cast);
415 let parent = match name_ref.syntax().parent() {
420 if let Some(segment) = ast::PathSegment::cast(parent.clone()) {
421 let path = segment.parent_path();
425 .and_then(ast::PathExpr::cast)
426 .and_then(|it| it.syntax().parent().and_then(ast::CallExpr::cast))
428 self.is_macro_call = path.syntax().parent().and_then(ast::MacroCall::cast).is_some();
429 self.is_pattern_call =
430 path.syntax().parent().and_then(ast::TupleStructPat::cast).is_some();
432 self.is_path_type = path.syntax().parent().and_then(ast::PathType::cast).is_some();
433 self.has_type_args = segment.generic_arg_list().is_some();
435 if let Some(path) = path_or_use_tree_qualifier(&path) {
436 self.path_qual = path
439 find_node_with_range::<ast::PathSegment>(
441 it.syntax().text_range(),
444 .map(|it| it.parent_path());
448 if let Some(segment) = path.segment() {
449 if segment.coloncolon_token().is_some() {
454 self.is_trivial_path = true;
456 // Find either enclosing expr statement (thing with `;`) or a
457 // block. If block, check that we are the last expr.
458 self.can_be_stmt = name_ref
462 if let Some(stmt) = ast::ExprStmt::cast(node.clone()) {
463 return Some(stmt.syntax().text_range() == name_ref.syntax().text_range());
465 if let Some(block) = ast::BlockExpr::cast(node) {
467 block.tail_expr().map(|e| e.syntax().text_range())
468 == Some(name_ref.syntax().text_range()),
474 self.is_expr = path.syntax().parent().and_then(ast::PathExpr::cast).is_some();
476 if let Some(off) = name_ref.syntax().text_range().start().checked_sub(2.into()) {
477 if let Some(if_expr) =
478 self.sema.find_node_at_offset_with_macros::<ast::IfExpr>(original_file, off)
480 if if_expr.syntax().text_range().end() < name_ref.syntax().text_range().start()
482 self.after_if = true;
487 if let Some(field_expr) = ast::FieldExpr::cast(parent.clone()) {
488 // The receiver comes before the point of insertion of the fake
489 // ident, so it should have the same range in the non-modified file
490 self.dot_receiver = field_expr
492 .map(|e| e.syntax().text_range())
493 .and_then(|r| find_node_with_range(original_file, r));
494 self.dot_receiver_is_ambiguous_float_literal =
495 if let Some(ast::Expr::Literal(l)) = &self.dot_receiver {
497 ast::LiteralKind::FloatNumber { .. } => l.token().text().ends_with('.'),
504 if let Some(method_call_expr) = ast::MethodCallExpr::cast(parent) {
506 self.dot_receiver = method_call_expr
508 .map(|e| e.syntax().text_range())
509 .and_then(|r| find_node_with_range(original_file, r));
515 fn find_node_with_range<N: AstNode>(syntax: &SyntaxNode, range: TextRange) -> Option<N> {
516 find_covering_element(syntax, range).ancestors().find_map(N::cast)
519 fn is_node<N: AstNode>(node: &SyntaxNode) -> bool {
520 match node.ancestors().find_map(N::cast) {
522 Some(n) => n.syntax().text_range() == node.text_range(),
526 fn path_or_use_tree_qualifier(path: &ast::Path) -> Option<ast::Path> {
527 if let Some(qual) = path.qualifier() {
530 let use_tree_list = path.syntax().ancestors().find_map(ast::UseTreeList::cast)?;
531 let use_tree = use_tree_list.syntax().parent().and_then(ast::UseTree::cast)?;